Adjustable permanent magnetic separator



July 19, 1960 NS 2,945,590

ADJUSTABLE PERMANENT MAGNETIC SEPARATOR Filed Oct. 7, 1955 2Sheets-Sheet 1 I /Z w //Z .2 a

IN V EN TOR.

Fa s we 1. H. TEHE A Tran/5Y6 July 19, 1960 ADJUSTABLE Filed Oct. 7,1955 R. H. STEARNS PERMANENT MAGNETIC SEPARATOR 2 Sheets-Sheet 2INVENTOR. Pow/54. H. Srsneu! Arra ENE v5 United States Patent ADJUSTABLEMAGNETIC SEPARATOR Roswell H. Stearns, Wauwatosa, Wis.,- assignor toIndiana General Corporation Filed Oct. 7, 1955, Ser. No. 539,162

14 Claims. (Cl. 209-423) This invention relates to an adjustablepermanent magnetic separator.

It has been found that in the type of magnetic separator in which a flowof water carries the material past the magnets, and the magnets are.electrically activated, high humidity and water leakage tend todamage'the electro magnets and cause either ineflicient separation orcomplete failure. Accordingly permanentmagnets are used, but with aunique mode of drum adjustment which provides the fine control madenecessary by the short range of action of permanent magnets comparedwith electromagnets, which is adaptable for either permanent orelectromagnetic separators, and which provides greater flexibility andsensitivity than is usual.

Novel means on the drum of the separator form a part of the flowchannel, in order to more efliciently channel the matter to be separatedwithin the eflective range of the magnetic field, and further cooperateswith novel flow plates underlying the drum. Means are provided tocorrelate adjustment in the magnetic field, adjustments in the flowplates underlying the drum, and adjustments in the concentrate dischargechute, in order tomaintain the proper operating relationship whenapplicants unique drum adjustment is used.

Also provided is an improved magnet support structure in which the softiron pole pieces providesupport for the magnets, reducing the bulk andcomplexity of the support structure, particularly in the region of themagnetic field, to facilitate the placing of'the magnetic poles as closeto the inside surface of the drum as possible and to reduce the weightof the structure for ready adjustability.

In the drawings:

Fig. 1 is a vertical axial cross-section of a magnetic separatorembodying my invention.

Fig. 2 is a view on line 22 of Fig. 1.

Fig. 3 is a view of the drum bearing, partially broken away to show amodified adjusting means.

Fig. 4 is a view on line 4-4 of Fig. 1 with the drum hub removed,showing a further modification of the bearing adjusting means.

The drawings show a drum having a cylindrical wall portion 11, twoannular flanges 12, and circular heads 13 having hub portions 14. On oneof'the hub portions is mounted a sprocket 15 which is keyed to the hubat 16. Hubs 14 are rotatively mounted on sleeves 17 each of which has acylindrical bearing surface '18 for its hub 14, an eccentric axial bore19, and a flange 20 which serves to maintain the drum structure in itsproper axial position and also serves as a worm wheel for ICC adjustmentof the eccentric sleeves 17. Each bearing sleeve 17 is mountedrotatively on shaft 21. Shaft 21 is supported at its ends by framemembers 22 in which it is rotatable, but it' is normally restrained fromrotation by set screws 23.

Insideof the drum two magnet supporting hubs 25 are keyed at 26 to shaft21. Extending from hubs 25 are spokes 27. An annular rim segment 28joints the distal ends of the spokes of each hub. Secured to the annularrim segments are pole pieces 29 constructed of soft iron and extendingaxially between the rim segments. Permanent magnets 30 of axiallyelongated horseshoe form are supported on the iron pole pieces and may'be secured thereto in any convenient manner. Proximate poles are oflike polarity and rest side by side on the polar bars 29. The poles maybe anchored. by screws, but gravity alone is suflicient.

The lower portion of the drum 11 lies Withintank 31 which is suppliedwith Water and ore from a curved entry passage 32' having a baffle 33and a lip 34 of arcuate cross-section, which guides the entering mixturein a smooth stream over flow plate 37 into intimate contact with therotating drum. Flow plate 37 is located just below lip 34, in a positionto receive the flow therefrom. It is adjustable about a pivot 39 locatedat its flow receiving end. Adjustment is effected by cam 40 whichismounted to rotate with adjustingshaft 41. Plate 37 has its marginalflanges 38 positioned between annular flange portions 42 of angularcorner members 12 of the drum 10, and serves to direct the flow ofseparatable material into regulated proximity to the drum periphery andwithin the effective range of magnet 30.

Tank 31 his two'sump portions 310 for tailings and 311 for middlingsdivided by a transverse portion 312. Nonmagnetic'solids falling off theend of flow plate 37 descend into the tailings sump 3'10 and are drawnoff from time to time through valves 43. Matter adhering to'the drumother than by magnetic force is-wiped off by rubber wiper .44 mounted onpartition 312 and sufliciently flexible to bear lightly against drumsurface 11.

Material which is susceptible of magnetic attraction adheres to thesurface of drum 11 by reason of the mag.- netic force concentrated inpole pieces 29, and passes scraper 44 without being dislodged. Thescraper will dislodge nonmagnetic material which is merely mechanicallyadherent. It will also Wash the magnetic material by holding backliquids'in which such material is immersed, thus occasioning relativemovement between the magnetic material and the liquid bath.

Flow table 46 having stiffening marginal flanges 47 is pivoted onshaft-49 and rests at its free end on adjusting cam'48. The plate 46 is'adjustable in the same manner as flow table 37 between the flangeportions 42 of the drum. Nozzles 50 mounted on pipe 51 are arranged :todirect jets of water against the concentrate on the drum and to causeallow of a sheet of Water in the channel defined by flow plate 46,fianges'42, and drum surface 1 1, which flow is counter to the rotationof theadiiurn. The effect of the jets from nozzles 50 may bevariedeither by varying the water pressure or :by .c'hangingthe angularposition of the nozzles by rotating pipe :51. .Nozzles 52 and-pipe 53:are similarly adjustable and provide :a third washing .of the magneticconcentrate. Jet. 52'-is-located close to the end of the angular extentof the magnetic field and tends to wash the concentrate ofi of the drum.

Dislodged weakly magnetic middlings flow back down plate 46 into sump311 for discharge subject to control valve 55. More strongly magneticconcentrates drop from the drum and flow onto chute 54 for delivery intoa conventional concentrate bin which is not shown.

Chute S4 is adjustable by means of rack 55 and pinion 56 to vary itsdistance from the drum for a purpose which will be indicated later.Further sprays may be provided at other points on the periphery of thedrum to wash off any concentrates which fail to fall of their own weightwhen removed from the magnetic field, in a man: ner well known in theart.

Each flange 20 of each bearing sleeve 17 comprises a worm gear havingteeth 57. A worm 58 meshes with each worm gear and is axially alignedbetween supports 59. A shaft 60 extends from the worm and passes throughframe member 61, terminating in a hand wheel 62 for the purpose ofrotating the bearing sleeve to adjust the position of the drum 10. Asthe bearing sleeves are rotated through equal angles the eccentric axisof the drum is likewise rotated.

Fig. 3 shows a modified form of adjusting means in which shaft 21 ischanneled at 70 to receive screw 71 which is engaged in threads in lug72, which lug projects axially from flange of bearing sleeve 17. Axiallyof flange 20 a set screw 73 penetrates into channel 74, which is anannular channel in the end of hub 14. In normal use of the machine, setscrew 71 is tightened in channel '70, locking bearing sleeve 17 to shaft21. Set screw 73 is not in contact with channel 74 and does not impedefree rotation of hub 14 on bearing sleeve 70. When it is desired toadjust sleeve 17, set screw 71 is loosened and set screw 73 istightened, so that hearing sleeve 17 is locked to hub 14 but is free torotate on shaft 21. The

from the magnets becomes particularly significant after the materialpasses scraper 44. Beyond the scraper the material moves counterflowrespecting water from jets 50 which is traversing table 46. Inconjunction with the counterflow of water from jets 50 the weakenedfield allows the washing of weakly magnetic middlings from the drum.These pass downwardly in middlings sump 311 to valve controlled outletspout 55, through which a flow of water proportioned to the influx ofwater is maintained.

Jets 52 dislodge strongly magnetic particles from the surface 11 of thedrum as they pass out of the magnetic field. Concentrate chute 54 isadjusted by means of rack 55 and pinion 56 in such a manner as to catchthese particles as they fall free of the drum surface.

The eccentricity of the bore in bearing sleeve 17 is calculated, withrespectto the distance from the bottom of the pole piece to shaft 21, sothat when the drum axis is at its highest point with respect to shaft21, the pole pieces 29 are a few thousandths of an inch from the innersurface of portion 11 of drum 10. This insures that the magnetic fluxmay be made very great at the drum surface radially outward from thethinnest portion of sleeve hearing 17, whereas radially outward from thethickest portion of sleeve bearing 17 (if that portion is adjusted sothat the magnets lie radially from that portion), the distance from thepole pieces to the drum surface is relatively great, and the magneticflux will be materially reduced. Thus it is possible to have not only afield of the desired intensity but zones of flux of differing intensityaccording to the adjustment of sleeve 17. For instance if the thinnestportion of bearing sleeve 17 is below the 4 axis of shaft 21 thestrongest zone of flux will be in the drum 10 is then turned until thecorrected position of ment means for hearing sleeves 17. Attached toflange 20 of bearing sleeve 17 is a stud shaft or pin 80 upon which acollar 81 is pivoted. Rod 83 connected to the collar extends through hub84 of a hand wheel 85. Hub 84 is rotatable in frame member 88 and is inthreaded connection with rod 83. Upon rotation of hand wheel 85 theshaft 83 is pushed or pulled according to the direction of rotation,thereby adjusting the angular position and the direction of eccentricityof the bore 17.

In operation, drum 10 being rotated conventionally by sprocket 15, thematerial to be separated enters inlet passage 32, is skimmed by baffle33 and passes over lip 34. Flow table 37 is adjusted into sufficientlyclose relation with the surface 11 of drum 10 so that magnetic materialin the mixture is attracted by the magnetized stationary pole pieces 29within the drum and clings to the non magnetic surface 11 of the drum.The changing field at the surface of the rotating drum as the magneticmaterial is rotated past the alternate north and south poles of themagnets produces movement among the magnetic particles. This facilitatesthe separation and dropping off of tailings and middlings. As thenonmagnetic tailings reach the turned down edge 64 of the flow table 37they drop downwardly in the bin 31. A flow of water proportioned to theflow of nonmagnetic tailings is withdrawn from region of scraper 44. Theintensity will be at a maximum throughout the entire angular extent ofthe magnets because the are formed by the pole pieces is concentric tothe arc of the inside of the drum.

However, if the thinnest portion of bearing sleeve 17 is between thecenter of shaft 21 and the pivot 39 of flow table 37 (as shown in Fig.2), the flux will be at a maximum near the flow distributing lip 34 andwill be greatly weakened at a point near jets 50 and 52. The converse lsituation can of course be effected as easily. The foregoing assumesthat the pole pieces are disposed on a segment of a cylinder as in thepreferred embodiment shown.

It will be noted that as bearing sleeve 17 is adjusted, the drum 10 as awhole, rather than the magnets, is

- raised or lowered. Since the magnets are very heavy,

this effects a substantial saving in the effort required. However, itbecomes necessary to adjust flow tables 37 and 46 to correspond to thenew position of the drum, in order to maintain the proper relationshipsbetween the flow tables and the drum for eflicient separating. Likespout43 in a well-known manner to avoid piling up of V wise it may becomenecessary to adjust jets 50 and 52, and it may also be necessary toadjust chute 54.

The water within the tank is maintained at the proper level by overflowpipe 35 from which water is discharged at 36.

If necessary the entire group of magnets may be rotated about its axisby loosening set screws 23 in pedestals 22 and rotating shaft 21 bymeans of a hand wheel or by any other appropriate means.

Since the field strength adjustment is made solely by rotating theeccentric bearings for the drum, the rotation of the magnet assemblyadjusts the flux cutoff point without appreciable change in distributionof field strength.

Thus the operator can change the operating characteristics of mymagnetic separator within a wide range, to

frame comprising end segments spaced axially of the drum and polar barsspaced circumferentially of; the inner periphery of the drum and inclose proximity thereto and connected with respective end segments, andpermanent magnets of channeled form in cross-section elongated axiallyof the drum and having polar ends mounted upon and supported by thepolar bars of the frame, proximate ends of the magnets being of likepolarity and being mounted on the same polar bar, said frame ends havingmounting means projecting at opposite ends of the drum and provided withsupports to which the mounting means is adjustably fixed, the drumhaving eccentric bearings rotatably adjustable respecting the mountingmeans and the drum being supported on the eccentric bearings in aposition of eccentricity with regard to said polar bars, the extent anddirection of eccentricity being adjustable by the rotation of saidbearing means.

2. In a magnetic separator, the combination with a rotatable drum andmeans for feeding to the periphery thereof material having a separablemagnetic content, of a set of magnets within the drum having outwardlydirected poles spaced circumferentially of the drum in arcuate series,the inner periphery of the drum progressively deviating in the directionof drum rotation from the arc of said series of poles, supporting meansfor the series of magnets within the drum, and bearings for the drummounted for rotatable adjustment respecting the supporting means andhaving bearing surfaces eccentric with respect to said supporting meansand upon which the drum rotates, the adjustment of said bearings beingadapted to vary the spacing and direction of eccentricity of the drumrespecting said arcuate series of poles.

3. The device of claim 2 in which the magnets are permanent magnets ofhorseshoe form in cross-section and elongated axially of the drum, themagnet supporting means comprising segmental end members, and the polescomprising bars connecting said members and upon which the ends of thepermanent magnets rest to constitute said bars as the arcuate series ofpoles aforesaid.

4. In a magnetic separator of the type described, the combination withsupports and a shaft extending therebetween, of bearing members mountedon the shaft for rotation with respect thereto and having bearingsurfaces eccentric respecting the shaft, a magnetic supporting framemounted on the shaft and comprising pole members spacedcircumferentially in arcuate series and magnets for energizing the polemembers, and a drum mounted on the eccentric bearing surfaces of saidbearing members and provided with means for its rotation, the innerperiphery of the drum being in immediate proximity to the arcuate seriesof polar members and progressively deviating therefrom in the directionof drum rotation, the extent and direction of eccentricity beingcontrollable by the rotation of the bearing members.

5. The device of claim 4 in combination with means for feeding to theperiphery of the drum material having a separable magnetic component andmeans advanced from the last mentioned means in the direction of drumrotation for catching tailings and magnetic concentrates.

6. The device of claim 5 in further combination with means for securingthe shaft in angular adjustment, the shaft and the magnets being bodilyadjustable respecting the supporting means for varying the point ofdischarge of concentrates.

7. In a magnetic separator, the combination with a drum provided withbearing means upon which it is rotatable, the bearing means havingmounting means in which the bearing means is rotatably adjustable, theaxis of the mounting means being eccentric with respect to the axis ofdrum rotation on said bearing means, of magnetic pole members in arcuateseries Within the drum,

said members being spaced circumferentially of the drum and disposedalong an arcuate path progressively deviating from the inner peripheryof the drum to an extent and direction determined by the position ofsaid bearing means, magnets forener gizing the pole members, a tank inwhich the periphery of the drum rotates, said being partitioned axiallyof the drum. to provide. separate collecting sumps for a less magneticand more magnetic material, means for introducing into the tank materialhaving a separable magnetic component, and means for confining theintroduced material respecting the drum periphery and comprising anarcuate plate having mountings upon which portions of the plate areadjustable to and from the drum.

8. The device of claim 7 in which said arcuate plate terminates adjacentthe partition, the partition having a flexible wiper extending towardthe drum periphery and positioned to engage material magnetically heldto such periphery as the drum rotates.

9. The device of claim 7 in further combination with a second platespaced axially of the drum in the direction of drum rotation from theplate first mentioned and likewise having mounting means upon whichportions of the second plate are adjustable to and from the drum, anddischarge means for concentrates extending from the periphery of thedrum outwardly of said tank at the end of the arcuate series of magneticmembers.

10. The device of claim 9 in which the respective plates have supportsat their mutually remote ends upon which the plates are pivoted, theplates having rotatable means for adjustably supporting their proximateends.

11. The device of claim 9 in which a flexible wiper extends from thetank partition toward the periphery of the drum in a position to act onmaterial carried with the periphery in the course of drum rotation.

12. In a magnetic separator, the combination with a drum mounted forrotation and means for feeding to the periphery of the drum materialhaving a separable magnetic content, of a frame disposed within the drumand with respect to which the drum is normally rotatable, magnetic polemeans disposed Within said drum and carried by said frame and havingpoles of successively opposite polarity disposed in arcuate fashion inclose proximity to and along the inner periphery of the drum, mountingmeans supporting said frame within said drum and projecting at oppositeends of the drum, supports to which the mounting means is adjustablyfixed, the drum having eccentric bearings rotatably adjustable withrespect to said mounting means, and the drum being supported on saideccentric bearings in a position of eccentricity with respect to saidpoles, the extent and direction of eccentricity being adjustable by therotation of said bearing means relative to said mounting means.

13. In a magnetic separator, the combination with a drum provided withbearing means upon which it is rotatable, the bearing means havingmounting means on which the bearing means is rotatably adjustable withthe axis of the mounting means being eccentric with respect to the axisof drum rotation on said bearing means, of magnetic pole members inarcuate series within the drum, said members being spacedcircumferentially of the drum and disposed along an arcuate pathprogressively deviating from the inner periphery of the drum to anextent and direction determined by the position of said bearing means. I

14. In a magnetic separator, the combination with a drum mounted forrotation on a longitudinal axis, of a permanent magnet assemblycomprising magnetic pole members spaced circumferentially of the drumand disposed along an arcuate path along the inner periphery of thedrum, permanent magnet means extending between successive pole membersfor establishing magnetic fields therebetween at the outer surface ofsaid drum, and means for adjusting the strength of the magnetic fieldsat the outer surface of said drum comprising incrementally operatingadjustment means continuously adjustable over a range of positions whilethe permanent magnet assembly remains stationary and without relativerotation between the magnet assembly and the drum to correspondinglyvary the strength of the magnetic fields-from the permanent magnetassembly.

Refereucc Cited in the file of this patent UNITED STATES PATENTS 306,778Ripley Oct. 21, 1884 500,604 Payne July 4, 1893 1,414,170 Bethke Apr.25, 1922 1 l l l 4 l

